Grinding wheel dresser



July 16, 1946. R. A. THOMPSON 2,404,148,

GRINDING WHEEL DRESSER Filed Aug. 5, 1944 3 Sheets-Sheet 1 July 16, 1946. R. A. THOMPSON GRINDING WHEEL DRESSER Y Filed Aug. 5, 1944 3 Sheets-Sheet 2 ,qrra/f/YEKs.

y 6. 9 6 R. A. THOMPSON"). 2,404,148

GRINDING WHEEL DRESSER Filed Aug. 5, 1944 3 Sheets-Sheet 3 flTroR/VEY Patented July 16, i946 GRlNDING WHEEL ,in'inssna I Richard A. Th mpson], Colonial Broach Com corporation of Delaware Nr OFFICE etroi t; assignorto i pany,- Detroit,'- Mich. a

Application August 5', 1944,. aa gqgisitif Thefpresent invention relates to a grindin wheel dre'sse'r'adapted to dress arcuate surfaces or straight line surfaces at any angle on the periph ery of a grinding wheel. It'isp'articularly adapted for use in dressing the wheels employed in grind ing splines or spline broaches, but may be em ployed for other purposes.

The primary object of the invention is to providea rugged, accurate, and simple dressing fixture adapted to dress awide variety: of wheel s-U... v Anotherobject of the invention is to provi de a dresser of the type mentioned in which allneces:

sary adjustments maybe flxed and determined by means of accurate measuring blocks such as the familiar Johannsen blocks. H p

Another object of the invention is to provide a machine of the type mentioned in which a minimum number of relatively moving parts are employed and in which, forany given formto be dressed, all relatively movable parts are fixed against relative motion except. two parts which move relatively to effect the desired motion of the dressing tool. n I 1 Another object of the invention is to provide a dresser of the type mentioned'in which means employed to adjust the location of the toolfor dressing straight surfaces is employedto effect the necessary movement of thetool in dressing curved forms and vice versa, thus increasing the versatility of the machine without correspondingly increasing its complexity. V v

Other objects and advantages of the invention will become apparent from the following specifi: cation, the accompanying drawings, and theappended claims.

In the drawings;

Figure 1 is a vertical section as viewed from the left side. 7 a v Figure 2 is a rear elevation of the invention with portions broken away to show the interior.

Figure 3 is a plan view of the invention. Figure 4 is a front elevation.

through the fixture Figure 5 is a fragmentary sectional view taken on the line 55 of Figure 1.

Figure 6 is a fragmentary section taken on the line 6-6 of Figure 1 showing the means for looking the dressing tool slide relative support therefor. v

Figure '7 is a diagrammatic illustration of one form of spline grinding dressed by the invention.

Figure8 is a diagrammatic view'of a second form of spline grinding wheel which may be dressed by the present invention,

to the rotary 4Claims. (Cl. 125-11) I p 2 j Referring to the drawings, and particularly to Figuresl to4 thereof,ithe dresser comprises a base plate I adapted to rest on the table of a grind: ing machine. The base plate is provided with-a splitkey formed by two pairs .of downward projections, each pair including projections. 2 and 3 which are formed as depending flanges on a pair'of plates .3 and 4 respectively, slidable toward and from each other in the'bottom of plate I The position of plates 3 and 4 is controlled by. means of a pair of adjusting screws '5 and 6 which. are mounted in countersunk openings in the, side edges of the plate I and are threaded into the members 3 and 4 respectively. A pair of cap screws I, indicated in dottedlines at the left-v hand side of Figure 2, are .fitte'din suitable slots in the members 3'and Lto retain them against the bottomsurface of theplate, I, with freedom for sliding movement relative to the plate'under the influence of the screws 5 and'6. The split key formedv by the projections 2 and 3 fits within the keywayon the table of a grinding machine. By adjusting the members 3 and 4 an accurate fit of the key in the keyway may be maintained. In addition, if the k'eyway becomes Worn it may be reground 'to a slightly greater. width by the I grinding wheel of the machine, and the split key adjusted to .fitthe increased width. This assures maintenance of the accuratelocation of the fixture as a Whole with respectitothe plane of the grinding wheel I 'The'base plate I is provided with a pair of upstanding apertured ears .8 'and 9 fitted'respectively with bushings I0 and II in which is journaled a shaft I2. The shaft is fixed against rota- 7 I! in which islformed a transverse bore I8. A pair:

I9 and Marc fitted within rotatably J'Qurnaled on the of flanged bushings thebore I8 and are shaft I2. I Apaifof spacing discs 2| and22 form wheel which may be an axial thrustjbeari'ng forgthe assembly,. and consequentlyaccurately locate the axial position of'the frame I I on the shaft I2.

Above the connecting portion ll of the frame I4'the frame is provided with a pair of side wall members 2 3"and1-2' I indicated in dotted lines in Figure ljand 3 and, also shown in sectionin Fi'gure..5'. The side wall members 23 and n netell d' to the 'frontafidbjack 0f members by means of the wall members 'vertical'slot as,

, ment on an axi 7 extension 44 or. the tube stem may move radially V movement is accomplished by;

of countersunk cap screws 25,-shown best in Figure 2, to form a rigid structure. The upper ends |5, H5, 23, and 24 are secured by similar cap screws 26 to a top plate 21. A generally rectangular fitted between the walls l5, I6, 23, and 24, and is slidable vertically therein, such slidingv movementbeing eifected b-y means; of a handle 2,9 fixed to the end Qfa double screw 30. The screw 30 has an upper portion 3| provided with a left-hand v thread and a lower portion 32 witha right-hand thread. The upper portion is a threaded bushing 33 fixed tothe top plate; 21,

block-shaped slide 28 The diamond may be mounted in any suitable mannerg' but two alternative mountings are illusthreaded-through r One of the illustrated ja ediu t draw n 7 While the lower portion 32 isjthiiwiddwi hin a v I threaded bushing 34 fixed to the slide 28. Asfa consequence of this arrangement rotation ofthe handle moves the slide vertically Within the frame I I tubular-spindle 4|.

.a notch 65 adapted to receive M in either direction. j V n V The slide 28 is provided with a circular'o-pening 35. extending parallel to the axis of the shaft 1.2 and adapted to receivea tubej36u The tube 36. is keyed'torthe slide 28, by means of akey 31 which isflocked in position The rearwall I of the frame is provided with a and the front wall Ifiis provided with a similar slot 49 through which slots the tube 3 6 projects freely. The slots are of sufiicient length to'permit the maximumverticalmovement of the slide 28 relative interference.

The tubular. stem 4|, of a rotary support 4; is journaled within the tube parallel to the shaft l2 under 43 keyed to a reduced 4|. of a key 46, and

the influence of a crank is fixed to the tube 35 by'means a similar disc 41 is hired to the tubular stem 4| by means of keyways 48 and a lock nut 49 by means of a setscrew 38.

to the frame l4 without 35 for rotary move-' ente of the nut 62 will lock the auxiliary slide 55 against radial movement, with respect, to the axis iiiheiubu l: sp n j r The auxiliary slide 55 carries the dressing tool which may be in the form of a pointed diamond.

diamon jholdefsfisin the form of a generally aired 63 ;having a stem 64 accurately fitted within. a suitable bore within the auxiliary slide 55 and extending parallel to the axis of the The stem 64 is provided with locking the holder inposition. The holderis also P i V QQ 'iW f an e 6 having n -P P.

tionffiiifwhich, as best shown in Figure l, fits Lwit'hinja keyway 59in the auxiliary slide and thus cylindrical element it which" in turn 'is fitted within a transverse opening in the holder 63 threaded on the reduced portion 44 of the stem 41; The disc 41 is provided, withan accurately the disc, the upper and lower holes 5| in the disc being vertically positioned relative to each other and parallel to the path of movement of the slide 28.. The holes 50 and 5| are adapted to have a, push fit with a bushing 52 fixed on a pin 53, having. a possibleto fix; the rotative position of the support '42'relative to the tube removed it will be obvious that the support is freely rotatable relative to the tube 36. n

An' auxiliary slide 55 is mounted upon the retary support 42 by means of the tongue. and

'Thejadjusted position r the auxiliary slide55. may; be ,fixed by means of 60, shown best in Figure sponds generally, to the shape of the dove-tailed,

a y. supp rt 2, a d tswi hinl OhEU-QQH h to the central portion of the dove-tailed groove in.

36 in any oneof four positions spaced '90? apart. When thepin 53is' aportion 58 at the lower end provided with a.

I As aflresult of this arrangement rotation .ofthe. screw. 56v shifts, the..- radial position of. the auxiliary slide 55 relative to the axisofthe tubular spindle 4|.

a wedge-shaped block 7 formed, hole 50,, and the disc 45'is provided withfour. similar holes, 5| spaced apart around handle 54. As a result, it is i the diamonds and lockedin; position by means of a long setscrew 12 shown' in dotted-lines in Figure 1'. The

opening in which the element 1| is mounted ex: tends parallel to the dove-tailed tongue and groove connectionbetween the auxiliary slide 55 and-therotary support 4-2.- If desired,'a second diamond 13' may be; similarly mounted further out on the holder 63 for use in connection with grinding wheels oi larger diameter. It will be understood that only one diamond will be elnployed at onetime.

In order'to increase the effective range'oi ad- J'ustment of" the diamond point by 7 the auxiliary slide 55 and.screwf55ji'a second diamond holder is provided which-positions'adiamond ata greater distance from the axis of the tubular spindle4| than does the holder36'3. This' holder, as shown in Figure 1, comprises abracket 14' fixed to the auxiliary slide 55 by means of a key'l5 and cap screws 16; It carries a diamond holding element provided'with a diamond point 18. Theelement His locked in position by means of a set screw 19p It will be observed that by rotating the spindle 4| through an angle of that'the diamond Hi-may be swung into the angular position occupied by 10* and 'l3, but will be spaced at a greater distance than the latter from the axis of the tubular spindle 4|. 7

The diamond holder 63 is so positioned on the slide 55 and the diamonds 1b and 13 areso posia the diamond point tioned relative to the holder, that. when the surface 8|! of the'block 59-contact's the surface 8| of the rotary support 42 the point of the diamond will be exactly on the axis ofspindle 4|. As a result,

the radius of movement of the diamond point efiected by'swinging'thecranlglhandle 43 maybe exactly determined by inserting measuring blocks betweenthe surfacesBil "and SI and thereaftergfixe inglthe auxiliary slide relative'to the rota y Support'42 by means of the wedge '50; The distance between the diamond point 18 and theaxes' Qfthe' tuular spindle V the surfaces 8!) and -8| arein contact, the distance between the point 18 and the .axisef; the pi d e 4| eq al them s a sets'crew 66 for 4|f preferably such, that when mumd t'ance tolwhich.

. inmate; shi ted sem nar; axis by means of the screW'56. Thus; the two diamond mountings double the effective: range of I m'ovementof the'auxillary slide 55-5 I As best shown'in the broken-away-portion :of

Figural-the side wall 23 of the frame I4 is provided with an opening 82 through which'may be inserted measuring blocks of known dimensions in order to determine the vertical position of the slide 28 relative to the frame "I4. fixed in the threaded bushing A pin: 83 is measuring blocks,'the distance betweenthe axes of the shaft I 2 and the tubular spindle M is known. Consequently the opening 82 and'the pins 83 and 84 provide a' means for accurately-determining the distancebetween those axes.

As best shown in Figure 2 the frame I4 is pro vided with'a pair of triangular boxlike proje'ct ing ears 85 and 85, to each of which is secured a cylindrical roll 81 and 89, respectively. The rolls are secured by'cap screws 89 inpos'itionagainst a pair of accurately locatedsurfaces- 90-and 9| formedonthe ears 85-, which surfaces extend at right angles to each other. The rolls-81' and' 88 are made'with great accuracy, and by the means 34 of the s1ide .28, and a pin 84 is fixed to the cover plate 21. These pins are so constructed that fora known distance between them, which may be determined by the J'ust'described are exactly located so that the common plane of their axes contains the axis of made fromthesurfaces will not be impaired'by any grinding dust which might fall on them. The rolls 81 and 88 in combination-with the locating blocks 92 and 93 provide a means by which the angular position of adjustment ofthe frame I4 about the axis ofthe shaft I2 may be accurately determined. For any given angle the distance between one of the rolls and its corresponding locating block maybe readily determined or calculated, and measuring blocks of the properdimensions inserted between the rolls and the cating block to accurately locate the angular position. v f I In order to fix' the frameI l inany adjusted angular position a-cla'mping' meansisprovided as best'shown in- Figure 5. As there shown, the lower portion ll of frame I4 is provided with a 'transversebore 94-in'which are slidably fitted a pair of plugs 95 and 90; The bore 94 intersects the bore I8, and the plugs 95 and-95 are provided with cylindrical surface portions 91- and. 98, respectively, adapted tofit'against'the'shaft I2. A socket head screw 99 extends through and is freely rotatable withrespec't to the plug 96, and is threaded through the plug 95 with the result that upon tightening of the screw the plugs will be drawn together'and clamped against the fixed shaft I2, thus preventing rotation ofthe frame relative to the shaft. 'In order to prevent free movement of the frame about the shaft I2 when the screw 99 is loosened, the screw is provided with a nut I00 which is fixed thereto in any'desired'manner, and a spring -IOI- surrounds thescrew and is located between the nutand the plug 95. Consequently, when the screw is loosened the spring maintains sufficient clamping action tending to draw the plugs together to prevent the frame from moving by gravity:

'Ijhe operation of the' mechanism may ;bestz.be: understood by reference todiagrammatic; Figures 7 and8. In Figure 7 is illustrated a iragnient ot a grinding wheel :I 02 adapted atov f'grindthe space between apair' of teeth, indicated indotted lines 104;:- of! a straight-sided splineifonsplined' broach having a @1'001': radius represented; b'ythe kiircle 1051M In: such a-xcasei the portion A- of' the face 'of the. grinding .wheel must be dressed f at I03 and teen arc equal to the radius of the circle I05. Forsuch: dressing operations the frame I4 is fixed in *a' verticalpos'ition'in which the rolls 81 and 88 are equal distances'from the locating blocks 92 and 93, respectively. This is accomplished; by

the use of anaccurate measuring block equal to. the known'distance between the plane of the ;up-1

per surfaces ofthe blocks 93 and the axis of shaft I 2 less the radius of the: rolls 81 and. The

main slide 28- is then elevated or lowered by means of the handle 29 until the axis of the spin-i dle'4I is onthe'center I05 of the cir'cle- I05. This is accomplished by inserting appropriate measuring blocks between the pins 83 and 84 shown in Figure 2 and adjusting th slide untilv the proper distance between those pins' -is achieved. This distance maybe calculated from.

theuknown distance between'theend ofpin I34 and the axis of the shaft I2, the known-distance between the end of pin 83and the axis of spindle 4|, and the known distanceshaft I2 and the axis I05 of the workpiecea auxiliary slide is then adjusted until the distance between the surfaces 80 and 8| is equal to the radius'of the circle I05i Then with the slides and clamped, the rotary support is oscillateddress the wheel. It willby' means'o f crank 43 to be understood inthis connection that the shaft I2 all timesparallel to the plane of the grinding wheel, and that in the dressing of a surface cor-.

the axis of responding with surface A in Figure 7 that theyare preferably located in the central plane of the Wheel. Pin 53 will be removed during this dressing operation in order that spindle 4I may rotate freely.

As a general rulegrinding machines for spline grinding maintain the work on a fixed axis and consequently-it is not necessary to change the:

I adjustment of the slide 28 to dress arcs of different radii. It is contemplated that the shop prints for the particular workpiecetobe'made will bear a notation'of the measuring block settings for the distance between the pins 83 and 84, distance 3 between the surfaces and 8I,- and the distance between the rolls-81 or 88 andt-he blocks'92 or 93; Consequently, no calculations need to be made by the operator of the machine. I

In order "to dress the straight sides B of the wheel I92 the main frame I4 is swung about the axis of the shaft from the vertical the profile B and equal'to the angle a between the central plane of the wheel. the frame I4 then occupies the line bb' the line b+b lying in the surface Btobe dressed; The spindle 4| is then .rotated in a counterclockwise direction from themeansv of pin 53; This results in an inclination of the. dovetailed point directed to the leftalong that line as-viewed in Figure 7. The small slide isithereupon adjust-i ed by screw 56 until the diamond point lies; in the line be-b; The small slidei-is thenclamped between thev axis: of

r The and the tubular spindle 41 are at I2 until itextends at an angleposition illustrated in the drawings and fixed in that position byways of slide 55 in a direction along the line c,c v ofFigure 7, with the diamond a "93. r The thickness of th'e measuring be "readily calculated 'sions of. the dresser.

dressing operation. the angular position of g by'tightening the clampin blocks indicated in dotted lines.

7 to approximate the V ofz the center ,ofrsuch anemic bylim'eans oft e trims nut fil andithe; wheel is dressed by1 rotating:.the: handle '29 "to shiftthe by means of measuring blocks-inserted between the roll 88 and thelbloick V or. determinedifrom ordinary trigonometric tables and the knowrrdimen- Likewise the, setting of the auxiliary slide 55 may be accurately calculated-to determine thelaccurate thicknesses of the meas- V I that the setting ofthe V mainframe on theiangle a maybe determined with: great accuracy blocks may 7 uring blocks to insert between the'surfaces B!) and" f 8 l l in orderto" insure that the diamond point will.

6-4) of Figure '7- duri-ng the It will be understood that the frame ,I 4' will be: fixed 95 andtt of Figure 5 prior to the dressing operation.

'It will. be appreciated that in order to the straight surface on the opposite side oft-he wheel it will'onlybe necessary to rotate the spindle 41 through an angle of 180 from the position it occupies in dressing the: surface 3, and to swing themain-frame l4 over to the opposite side be upon the line of the planeof the wheel at the same, butv oppoe, site, angle"; 7' .r, i l

Theldresserisaal'so adapted'ito dress arcuate sidg'areassuch as thearea. Con thejwheel I09" indicated'diagrammatically in Figure 8; Any de-' sired arrangement of arcuate side surfaces may be 'dressed,-but, in, the particular example illus- V trated, C is an arcuate; grinding profile which is intended to approximate the involuteform redress to'fi x-the radius-in is employed to feed the f 'ing. of straightiprofiles,

quired to dress the sides ofinvolute splined-teeth In this connection it may be noted that on small splines it ispossible involute curve with great accuracy by a true circulararc or, in some cases, a combination of two tangent arcs of different radii. The center or centers of such arcs and theirradii may be determined bymathematical calculation or by laying out the true involute on a greatly enlarged scale, such as fifty to one hundred or one hundred toone, and determining the center location and radius of the proper circular arc-or arcs graphically; In either event, inaccorda-nc'e'with the present invention, the location are, indicated at H0 in Figure 8; is determined with respect to the axis of the shaft l2 and,in addition, a determination is made' of the angle at between the central plane of the wheel and the line bb' of Figure 8,"which extends through the center I ID of the arc and the axis of the shaft i2.

small. slide 55 is then adjustedby screw Eli-"untilthe distance between the surfaces: SOI -8| equals the radius of the arc, C,lwhich is-to' bedressed. This position of the small slide 55' is fixed by means of the thumb nut 62' and the wheel is then dressed'by swinging the-diamondpoint about the axis of the spindle M by manipulation of the handie-43. The OPPOSltGSidG'OfthGl wheel may be dressed in the'same-m'amier. without any'adjustment eiiceptia shift "of the mainframe l4 to the until the coincides with the. center said frame; said reference with great (accuracy blocks, In addition it proper angular position ionitheoopposite side of the frame of therwhe'el;

i right side of the wheel as viewed. in Figure 8.

It'will be observed that there is provided; in accordance With' the, present invention, arelatively simple dressing ,device of rugged construe tion in which all adjustments may be determinedby means of measuring 7 will be noted that the device is: flexible incapacity to; dress various arrangements of straight or arcuate profiles but that such: flexibility is not achieved by additional complication of the mechanism, Thus, the rotary movement. of the diamond provided by the pivotal mounting of spindle M is employed to perform the dressing operation in the case of arcuate profiles andqis employed to adjustthe diamond into apos'ition at right angles to the surface to be dressed when dressing straight profiles. The sliding movement of the small slide 55- isutilized dressing arcuate vprofiles and tact with the; wheel 'in'preparation for the dress-- The main slide'is em ployed to position thespindle 4| on the center ,of an arcuate-pprofile andis employed to effect the rectilinear dressing movement in dressing a straightprofile. Finally,- the swinging movement of the frame 14 is employed to locate the axis ofthe spindle M onthe center of an; arcuate profile to bedressed, and is employed to adjust the plane of movem ntof the diamond to correspond to-the angular position of a straight profile; towbe. dressed, Thus, each of the relative movements oradjustments provided in the machine is employed in dressing; both types of proj files and no additional adjusting means essary for either type; 7

What i'sclaimed is: V g

l.- A grinding wheel dresser comprisinga base, a frame pivotally connected to the base, a slide movableon the frame in a path at rightangles to the axis of said pivotal oonnection, a. support rotatablypmounted on said slide on an axis parare necallel to; said first mentioned axis a second slide 7 movable on said; support in a path at rightangles tot-heaxisof movement of the support relative to the first slide, and a dressing tool carried by saidsecond slide with its point projecting in a direction. parallel to; the path of movement of the secondslide relative to the support, said basehavinga flat reference'surface extending parallel to" theaxis of said frame, and means on sa1d"fr am'e" offset from its-axisdefining a curved surface adapted to remain tangent to planes parallel to said referencesurface, in allpivotal positions of surface and said means being in juxtaposition to receive between them measuring blocks for determining the angle of adjustmentof the frame relative to the base,

2; A grinding wheeldresser comprising a base,

a frame pivotally connected to the base, a slide movable on the frame in a path at right angles tothe axis-of said pivotal connection, a support rotatably mounted on said slide on an axisparallel to: said first mentioned axis,v a second slide movable on said: supportirr a'path at right angles tothe axis of movement-of the support relativeto the first slide, and a dressing toolcarried by said second slide with its point projecting in a direction' parallel tothe pathof movement of the second slide relativeand second slide: havingzsurface:portions which diamond point into com I tothe support, said support move toward and from each other and remain in alignment during movements of the second'slide relative 'to the support and between which measuring blocks may be inserted to determine the adjustment of the dressing tool relative to the axis of the support.

3. A grinding wheel dresser comprising a base, a frame pivotally connected to the base, a slide movable on the frame in a path at right angles to the axis of said pivotal connection, a support rotatably mounted on said slide on an axis parallel to said first mentioned axis, a second slide movable on said support in a path at right angles to the axis of movement of the support relative to the first slide, and a dressing tool carried by said second slide with its point projecting in a direction parallel to the path of movement of the second slide relative to the support, said support and second slide having surface portions which move toward and from each other and remain in alignment during movements of the second slide relative to the support and between which measuring block may be inserted to determine the adjustment of the dressing tool relative to the .10 axis of the support, and said dressing tool being so positioned on said second slide that its Wheel engaging point is located on the axis of the support when said surface portions contact each other.

4. A grinding wheel dresser comprisinga base, a frame pivotally connected to the base, a slide movable on the frame in a path at right angles to the axis of said pivotal connection, a support rotatably mounted on said slide on an axis parallel to said first mentioned axis, a second slide movable on said support in a path at right angles to the axis of movement of the support relative to the first slide, a dressing tool carried by said,

point projecting in a dime-- second slide with its tion parallel to the path of movement of the second slide relative to the support, and means for fixing the support relative to the first slide in either of two rotative positions 180 apart, in both of which positions the point of the dressing tool projects in a plane at right angles to the direction of movement of the first slide relative to the frame.

RICHARD A. THOMPSON. 

